Lens surfacing machine



Jan'. 17, 1939. l, N, CASSITY 2,144,179 LENS SURFACINQMACHIN Filed July l2, 1957 2 Sheets-Sheet l lhwenfor Isaac/@144022 C/assz LENS SURFAC TNG MACHINE Filed July 12, 193i7` 2 Sheets-Sheet 2 Patented Jan. 17, 1939 UNITED STATES .PATENTv OFFICE Claims.

This invention relates to lens grinding and polishing machines and has for its general object to provide apparatus whereby cylinder grinding and polishing machines involving Va back and 5` forth reciprocatio-n of a lens over a lap, Vmay be readily adapted to the surfacing of spherical lenses. As examples of reciprocating cylinder surfacing machines reference may be had to United States Letters Patent Nos. 940,978 and 1,709,943.

Another object of the invention is to make"r it possible to grind high and low curves, on such machines as disclosed in said patents, on spherical or cylindrical lenses.

With the vgeneral objects named in View and others as will hereinafter appear, the invention consists in certain new and useful features of construction and organization of parts as are hereinafter described and claimed; and in order that it may be fully understood, reference is to be had to the accompanying drawings, in which:

Figure 1 is a plan view of a lens grinding machine embodying the invention, certain conventional parts of the machine being omitted.

Figure 2 is a side elevation of the same, but discloses somefconventional features omitted from Figure 1, and also shows the housing broken away to indicate part of the mechanism for imparting forward and lateral movement of the .lensholder or block carrier.

Figure 3 is a vertical section of the construction jas disclosed in Figure 1, the section being on the line III-III of Figure 2.

Figure 4 is a fragmental horizontal section somewhat enlarged, on the line IV-IV of Figure 3.

Figure 5 is a vertical section on the line V-V of Figure 4. y

Figure 6 is an inverted plan View of the arm and the clamp jaws for carrying the lens holder or block.

Figure 7 is an inverted plan of the lever` and pawl for imparting step-by-step rotation to the lens holder.

Figure 8 is a detail perspective of the pawl holder carried by the lever of Figure 7.

Figure 9` is a detail vertical section through the ratchet wheel and. lever-carried housing cap.

Figure 10 is a fragmental View showing the 'shaft to which the ratchet Wheel is interlocked, said shaft in thisigure, also being interlocked with the reciprocating driving arm to prevent rotation of the lens, this: arrangement being used when cylinder lenses are beingsurfaced.

' Figure 11 is a cross section. through a modified form of support for the lap, wherein the center of rocking movement is below the rocking operating surface of the lap, instead of above as in the other iigures of the drawings.

In the said drawings, where like reference 5 characters identify corresponding parts in all of the gures, I is a housing for such machine mechanisms as disclosed in the patents mentioned for simultaneously imparting lateral and longitudinal reciprocatory .or oscillatory motion l0 to an arm 2Aprojecting forwardly from the housing, the forward extremity of said arm being held yieldingly depressed byaspring-actuated rod 3, 'and limited in such depression by a strap 4. These parts are carried by an adjustable support 15 5 carried by the housing, a complete disclosure being had by reference to the patents aforesaid.

A substantially U-shaped bracket 6 is secured to the front of the housing I and it is equipped With a pair of forwardly projecting parallel arms 20 l. Clamped upon one of said arms is a. sleeve 3 forming a support for upper and lower arms 9 and I0 constituting journals for an upright slotted post II which rests upon the upper arm 9 and is retained against upward movement by a 25 nut I2 underlying the lower arm, said post being free to turn in either direction, as will hereinafter appear.

The arms 'I also adjustably carry sleeves I3 having hardened conical sockets I4 in their up- 30 per sides. Pivotally engaging said sockets are upright pins I5 clamped above their pivotal points in lateral arms I6 of a pair of substantially semi-circular hangers I1, secured at their lower ends in a lower plane than the pivotal 35 points of said pins, upon opposite arms I8 of an angle bracket I9. Said bracket has forwardlyprojecting vertical ears 20, between and upon which is pivoted a clamp jaw 2| carrying an actuating screw 22.

A lap 23 is secured upon the angle bracket I9 in any suitable manner and its lower portion has a flattened face for clamping engagement by the jaw 2|, the upper face o-f the lap having the curve to which a lens is being surfaced. As shown 45 the upper face of the lamp is concave and has a felt facing 25. The lens 26 to be surfaced is cemented or otherwise .rigidly secured to the lower side of a lens block 21.

The lens block 2l has an upstanding rib 28 50 clamped between a pair of jaws 29 hinged together and to the lower end of an upright shaft 39 journaled in an anti-friction bearing 3| secured in the arm 2. The arm 2 has a recess 32 adapted for engagement with a lug 3,3 projecting upwardly from one of the jaws (see Figure 10), when it is desirable to lock the shaft 30 against turning about its own axis, namely, when cylinder lenses are to be Worked. In the grinding of spherical lenses this rotating movement is essential, and to obtain this result a spacer 34 is fitted loosely around shaft 30 between the arm 2 and the jaws 29, and is provided with an opening 35 to receive the lug 33 and thus guard against the interlocking of the shaft and the arm 2.

The shaft 30 has a groove 36 engaged by a lug 31 projecting from a ratchet wheel 38 mounted on the shaft and within a circular wall 39 rising from said arm. The wall has an lopening 40 snugly receiving a detent 4I secured in a casing 42 rigid with arm 2, and containing a spring 43 for urging the detent yieldingly against the ratchet Wheel to prevent back rotation thereof. The wall 39 also has an opening 44 for oscillatory play therein of a pawl 45 mounted in a casing 46 secured to a lever 41 extending through the slotted post II, said lever having a cap tting snugly but rotatably upon the wall 39. The wall of the cap has an opening 48 to accommodate the pawl and an opening 49 to receive the inner end of the detent 4I, the latter opening like the wall opening 44, being wide enough to permit the desired extent of thrust and return operations of the pawl to effect intermittent rotation of the ratchet wheel and hence corresponding action of the lens holding block. It will be understood that the varying movements of the arm 2, which impart forward swinging movement of the arm affect proportional' turning movements of the `lens through the fact the ratchet operating lever 41 is engaged with the slotted post II carried by the housing. 'Ihe openings 44 and 49 of the walland cap respectively are of extent to accommodate the maximum swing of the lever 41. Upon reverse movement of the ratchet on rearward reciprocation of the arm 2', back rotation of the ratchet is prevented by the detent 4I.

A clamp nut handle 5I) is engaged with the upper end of shaft 3l), anda washer 5I is interposed between said handle and the cap of the lever, the handle being used to clamp the jaws 29 to hold the lens block. The lever 41 has longitudinal play in the slotted post II suicient to accommodate all lens movements on the lap, and the post I I serves as the fulcrum in holding the end of the lever against movement when the arm 2 isreciprocated, whereby the lens is axially rotated step-'by-step. When the lens holder is interlocked with the arm 2 (Figure 10), as in the grinding of high or low curve cylinders, thelever 41 is disengaged entirely from the post, either by providing it with a break-joint or removing it or the post I I from position.

In order to prevent the lenses from being disengaged from the lap, particularly when lenses of small radius are being ground or polished, the lap is mounted so that it rocks on the pivots I4-I5, the forward and backward strokeY of the arm 2 being adjusted so that the lens in traversing the lap never rocks the latter to such extent as to cause disengagement of pivots'I4-I5. This construction insures that the downward pressure of the lens on the lap is always at substantially right angles to the plane of contact between the lens and lap. In Figure 11 a rocking support from below the operative face of the lap is shown, in which a bar 55 is rigidly carried by the framework of the machine, and mounted thereon are a pair of upright pins 56. The under surface of the lap is formed with a pair of recesses 51 which rockingly receive the pins 56.

From the above description and drawings, it will be apparent that I have produced a construction embodying all of the features 'of advantage set forth as desirable, and `while I have described and illustrated the preferred embodiment, it is to be understood that I reserve the right to all changes falling within the principle of the invention and without the ambit of the prior art.

I claim:

1. In a lens surfacing machine, the combination of a support, a lens holding arm carried by the support and being constantly driven backwardly and forwardly, an abutment member carried by the support, a lap carried by the support, an axially rotatable lens block secured to the reciprocating arm, and means associated with the lens block and abutment for imparting stepby-step rotation to the former concurrently with the movement of the holding arm.

2.'In a lens surfacing machine, the combination with a support, a lens holding arm carried by the support and being constantly driven backwardly and forwardly, an oscillating abutment member carried by the support, a lap carried by the support, an axially rotatable lens block secured to said reciprocating arm, a ratchet for imparting step by step rotation to the lens block, and an arm connected at one end to the ratchet and at its other end to the abutment for actuating the ratchet in response to the reciprocation of the arm.

3.` In a lens surfacing machine, the combination with a support, a lens holding arm carried by the support and being constantly driven backwardly and forwardly, a lap rockingly mounted on the support, an abutment member bearing a fixed relation to the support, an axially rotatable lens block secured to the reciprocating arm, and means associated with the lens block and abutment for imparting step-by-step rotation to the former concurrently with the movement of the holding arm.

4. In a lens surfacing machine, the combination with a support, a lens holding arm carried by the support and being constantly driven backwardly and forwardly, a pair of arms forwardly projecting from the support, a lap rockingly suspended from said arms, an axially rotatable lens block secured to the reciprocating arm, an abutment member bearing a xed relation to the support, and means associated with the lens block and abutment for imparting step-by-step rotation to the former concurrently with the movement of the holding arm.

5. In a lens surfacing machine, the combination with a support, a lens holding arm carried by the support and being constantly driven backwardly and forwardly, a pair of arms forwardly projecting from the support, a lap rockingly suspended from and longitudinally adjustable on said arms, an axially rotatable lens block secured to the reciprocating arm, an abutment member bearing a xed relation to the support,

and means associated'with the lens block and abutment for imparting step-by-step rotation to theformer concurrently with the movement of theholding arm.

` ISAAC N. CASSITY. 

